Respirator



Jan. 8, 1952 Filed Aug. 2. 1949 C. C. WILM RESPIRATOR 5 Sheets-Sheet lCARL. C. WILM,

ATTORNEY Jan. 8, 1952 c. c. WILM 2,581,893

RESPIRATOR Filed Aug. 2, 1949 3 Sheets-Sheet 2 FIG.2.

CARL C. WILM,

ATTORNEY Jan. 8, 1952 c. c. WILM 2,581,893

REsPIRA'mB Filed Aug; 2, 1949 s Sheets- Sheet :5

F l G. 9.

'll/9j mi mi 2 w I06 I07 I03 |o4 FIG. IO. F l G. |2

' INVENTOR: F G. 8. CARL C. WILM,

ATTOR-NEY pressure; I may go tobetween 12to' 15 millimeters of'mer-Patented Jan. 8, 1952 Carl 0. Wilm, Denver, 0010., ass gns J. J.Monaghan Company, 1110., Denver, 0010., a corrotation '01 ColoradoApplication'August 2, 1949,-SerialrNo. 108,139

vG'Ilil a'ims. 1

:This inventionrelates to respirators and comprises' an improvement overthat shown in; my

paterrt;applicationv Serial No. 735,162, filed. March :17, 19.47, nowPatent No. 2,490,395. vTh at appli- -Jcatio,n discloses a power-drivenl'respirator for patients whose lung-motivating muscleshavezbeemrendered: deficient by para1ysis; such in cases of polio sufferers.The inhaling and ex- -.-ha1ing ofvair by the lungs is facilitated .bmeical means applying cyclically compression and,.e'xpansion through themedium of alternate positive and-negative pressured.- air-flows set upwithin a torso-engaging plastic convexrigid shell or breast-platefitting tightly over the thorax of st'he patient. A flexible conduitleads from the shell on the patient to an instrument casing containing adevice adapted to apply. air-flows to the conduit-alternately undercompression and suction. The suction stroke or negativepressure causesthe patients lungs to expand (and inhale) breath w-hilethe compressionstroke or positive --pres sure causes the patients lungs to compress=(and1exhale) breath. The rhythm of the cycle is controlled toapproximate or simulate the pa -tientsl normal breathing. vThe degreeof. posi- '-:tive-and:negative pressure of the air-flows iscontrollableby valves-because the negative pressure usually is made moreintense than the positive For instance, the negative pressure .curywhile the positive pressure may go to between- 2 to .4 millimeters. Thereasonfor this'low positive pressure is that gravity and automaticcontraction of chest muscles'help in the exhaling action. y l

- So one of the objects of this invention is' to devise devicesassociated with theconduit going to the shell on the patient from thecompressor or its" equivalent, which can be adjusted to'control .thesepositive and'n'egative pressured air-flows to the degree bestsuited tothe patient A corollary tothis is that since it is important to knowvery accurately the degree of these pressures being-applied to. .thepatient's thorax, another olsrject of this invention isto deviseapparatus by; which suchj pressures can bemeasured directly at-.their-pla ce of application, rather than merely v ,2 tween air-flow.andconduit-surface, so it :i'sanother object of this invention to devisemeans for measuringflthese pressures by a gauge on the power. unitcasingvand thus closelyfladjacent to the pressure controls and yetmeasuring them directly at the 'patients thorax through the medium of apressure conveying or transmitting device through which theseoppositely-"directed flows of air do not pass. The conduit, forconvenience in transportation, is usually made detachable both from theshell and from thel'power unit or instrument casing. When so detached,an operatoris apt to start the compressor in the casing and then puthishand over the outlet aperture in .the casingto which the conduit isconnectible .withthe result that the back pressure so placed on thecompressor will break some part in it or its operating mechanism-which,

after all, is only devised to compress upto about 1% of a pound. So itis a further object of this invention to devise and arrangera safetymechanism to relieve "such abnormal pressures 'without damage to theoperating'parts yet which a1- low-theparts to go back to normaloperation as soon as the cause of such high pressure. is removed.

The environment of this invention is a shell tightly fitted to thepatients torso "with 'aflexible air-fiow conducting "conduit leadingfrom that shell tov an instrument casing wherein there is mechanism forproducing cyclicallyin'the conduit a flow of 'compres'sed'air in adirection toward the shell followed by a flow of reduced pressure air inthereverse direction; namely, away'from the shell and toward the casing.In the casing is a gauge indicating and measuring plusand minuspressures. In this environment, it is one ofthe features of thisinvention to provide in the conduit a small diameter tube projectingfrom the shell-end of the conduit and leading through the conduit to beconnected tothe pressure'gauge in the casingwhile functionallyremotef-romthe air-flows and the atmosphere.

Iii-thisenvironment, it is anotherfeature of this invention to associatewith th-e conduit closely adjacent to thepressure gauge a valve mechainism oi special construction which permit's the operator to control.adjustably the degree sofzposi- *tivepressure and the degree of=negativepressure passing through the conduityto the shell :on

.the. patient. vIncluded in :this special construcopening in alturnablegate as correlated with a 66-- coacting opening in ,a plate abuttingthegate.

'eter of the larger flexible conduit does.

The co-operating openings or apertures are generally in the shape of acomet with a curved tail or perhaps more nearly the shape of anapostrophe but with the apostrophes oppositely directed for givingunusually accurate control. One valve is provided for letting air intothe conduit while another valve is for emitting air from the conduit.The latter valve is pressure closed, preferably by a flexible domedclosure that, however, is inflexible enough to prevent emission of airuntil the pressure of air within the conduit there'- against is greatenough to flex the closure.

In this environment, it is another feature of this invention to use forcreating the plusand 4 flexible conduit and a torso-engaging shell, aportion only of the shell being shown.

Fig. 6 is a fragmentary section of a cylinder which forms a part of thisapparatus and shows, partly in section therein, a piston having a.special resilient peripheral gasket.

Fig, 7 is an enlarged fragmentary detail of a part of a valve"assembly"and' is taken approximately along'line 1-1 of Fig. 4, lookingin the direction indicated by the arrows.

Fig. 8 is a sectional elevational view taken in a plane along the line8--8 of Fig. 7.

pheral gasket which collapses or bends over when dangerously abnormalpressure backs up against the piston, thus letting the pressure escapeto the opposite or back of the piston to establish a lessened or normalpressure within the system, whereby the abnormal pressure is dissipated,and whereupon the gasket returns to normal cylinder-contacting andair-compressing position.

A feature of advantage of the small tube within the larger flexibleconduit is that since the wall of the small tube is acted upon by thealternating pressures inside of the larger conduit, the final effect isfor the elimination of variation of volume inside the tube with theresultant increase in accuracy of measurement of the pressures actingupon the patient within the shell of the respirator. When pressure isincreased inside of the conduit, pressure is simultaneously increased inthe tube. When pressure is decreased in the conduit, pressure issimultaneous- 'ly decreased in the tube. The result is that the tubesdiameter does not vary whereas the diam- This measurement of pressurethrough the tube avoids errors of indication if the measurementis of thepressures within the larger conduit because the conduit is beingsubjected constantly to oscillating pressures and vacuums so that itsvolume changes accordingly and seriously affectsaccuracy of measurement.These inaccuracies are avoided by the use of the small tube especiallysince its non-shell end terminates within the pressure gauge and thus isnot open to the atmosphere or to the variable pressure-producingcompressor.

The best embodiment of this invention now known to me has been chosenfor the purpose of illustration but it is described hereinafter as anexample 'of the invention used for illustrative purposes so it is to berecalled that equivale'nts of certain parts and functions can be used.The example hasbeen illustrated in the accompanying drawings, in which:

Figure '1 is an elevational open rear view of the apparatus showing themechanism within the casing, and includes a pair of torso-engaging rigidshells or breast plates, parts being broken away to better illustratesame.

' Figure 2 is a perspective front view of the case without the connectedtorso-engaging shells.

Fig. 3is an enlarged fragmentary detail of a valve'assembly forming apart of the apparatus. Fig. 4 is a sectional elevational view of sametaken along a plane indicated by-the line 44 -of Figs. 2 and 3. Fig. 5is a fragmentary detail, partly in section,

showing a connection between the end of a Fig. 9 is a plan view of apart removed from i 1 1 Fig. 10 is a side elevational view of same.

Fig. 11 is a'bottom plan view of a part removed from Figure 7; and

Fig.1.; is a sectional elevation of same taken along the line |2--|2 ofFig. 11.

Referring to the parts in detail, designates a casing or housing havinga bottom |2, side walls |3, top l4, lower front wall l5, a beveledfront-top l6, and a rear panel H which is] hinged to the bottom l2 byhinges l8 and is provided with looking tongues (not shown) which engagespring clips l9 when the rear panel I1 is closed. A carrying handle 20may ly movable therein. A shaft 23 is attached to" the piston 22 and isgiven reciprocal movement by its connection to a crank arm 24 which issecured upon a shaft 25 extending through the casing of gear-reductionunit 26. A set screw 21 secures the crank arm 24 upon the shaft 25. Anelectric motor 28 is geared to and drives the gear-reducing unit torotate the crank arm 24 and impart reciprocal movement to the shaft 23and its connected piston 22. Electrical energy is transmitted to themotor 28 through an elec trically-connected voltage-reducing transformer29 which is, in turn, supplied with current from its source by aconventional conductor 38 and its attached plug 3|.

shaft 23 by means of a wing-headed pin 32 which is threaded upon theouter end of the crank arm 24 and engages a slottedcross-head 33 formedupon the end of the piston shaft 23. A speed control knob 34, connectingwith a governor in a governor casing 35, supplies a means to regu latethe revolutions of the motor 28.

' Conduits 36 and 3'! connect with the compartments of the cylinder 2|through orifices in the cylinder heads 38 and 39, respectively. From,

and project through orifices 44 (Figs. 3 and l) the side walls |3.Flexible and resilient conduits 45 and 46 (which may be corrugatedtransversely) having tapered connection thimbles '41 and 48, are at-;tached, at one end, to the tubular valve units 40] and 4|, respectively(Figs. 1,- 3 and i); and at their other ends'are attached to thetransparent plastic domes 49 and 50 oftorso-engagi'ng shells.

or breast plates 5| and 52,'respectively. Upon the dome attachment endsof the flexiblecom duits 45 and 46 are tapered connecting thimblesj 53and 54, which fitsnugly'into bevel-walled; tubes or-rings 55 and 56,"respectively. These" The outer end of the crank arm 24 is detachablyconnected to the piston 1 a liances rings are' securely attached inorifices "tothe domes :49 and'SOKFig; '5). The torso-*engaging-shellsi'l'and SZFareeach provided'with a suitable strap and clasp51fand58irespectively, as a means for tightly attaching thetorso-engaging shells over "the thorax of a patient. 'When-a singlepatient isjtobe treated, one of the torso-"engaging'shellsandits'connecting conduit may be disconnected from the apparatus.Inflatable, resilient 'and "flexible'gashets 59 and are attached along-the edges of "the torso-engaging shells -5-l and 52, "respectivelyfandprovide the means for effecting a'ftight juncture with the body of thepatient.

' As the piston 22 is givenreciprocalmotion in .its cylinder 2|,air-flows are created in' the con- 'duits 45 Mid, between theirattachedtorsoengaging'shells 5| and '52, and the compartments injthe'cylinder '21 formed by the p-iston22- and :the' cylinder "head 39 andbetween the piston 22 and the cylinder head 38, which -are alternatelyunder compression and suction. The suction stroke or negative pressurecauses the patients 'lun'gsto expand (inhale) breath while thecornpressionstroke or positive pressure causes the patients lungs tocompress (exhale) breath. The'degree' of positive and negative pressureof *theair-flows'is controllable by valves, the megativepressure usuallybeing made more intense than the positive pressure. The negativepressure may go to between 12 to 15 millimeters of *m'ercury'readingwhile the positive pressure-may go to between 2 to 4 millimeters.

Controlling means'for regulating the positive and negative air-flows areprovided and consist of the arrangement of parts in connection with'the' tubular valve units 46 and 4|, heretofore imentionedi For thepurpose of simplicity of description, asingle tubular valve unit 4| willbe 'described the' other tubular valve unit 49 being n identical inparts, arrangement and action. Extending from and'integrally formed uponthe tubular valve unit 4! (Figs B and 5), are dual cylindrical valvepockets 6| and 62, which are capped with cover plates 63 and 64,respectively. An'attachm'entstud 65 upon the tubular valve unit betweenthe'cylindrical pockets provides a means-for attachment to the bevelfront l6 of the casing II and is held thereto by a screw 66. The coverplates 63 and 64 are secured upon the cylindrical valve pockets 6| and62, respectively,

by screws 61. a Abuttinjg turntable valve-plates 69 and 69 areconcentrically mounted upon the cover plates 63 and 64-,- respectively,and are given partial rotation thereon by means of a shaft 10 to whichthe 1:

turntable valve plate 68 is pinned and a shaft II to which the turntablevalve plate-69 is pinned. Theshafts' 16 and 1| extend upwardly throughthe beveled top l6 of the casing H and have, v

tively, while the abutting turntable valve plates 68 and 69 aresimilarly formed with apostropheshaped apertures 18 and 19. Theapostropheshaped apertures in the turntable valve plates are broughtinto perfect alignment with the apostrophe-shaped apertures in the coverplates when the turntablevalve plates are turned clockwise or in thedirectionind-icated'by th arrow X shown in 3, thereby fully opening" theair passages to the valve pockets G land 62. By rotating the'turn'table'valve plates in an opposite-direction orcounter-clockwise,the apostrophe-shaped aperturesthereon may be turned out of align- 'mentwith their co-o-perating apostrophe-shaped apertures in the abuttingcover plates to close-the air passage to the valve pockets. Variousdegrees or sizes of air passages through the 'apostrophee shapedopenings may be-attained from minimum pin-head-sized openings to the--full-sized .-.openings at'tainedwhen-the coinciding apostropheshapedapertures are aligned. 1 Lugs Bik -Bland "8283- are formed upon theperiphery of the turntable valve-plates 68 and 69, respectively, andengage stop pins 84 and 85 upon the respective ccver-plates63 and 64 tolimit thev turning movement in either direction of the turntablevalve-plates. J i To visually indicate the pressure, either positive ornegative, in the torso-engaging shells 5! and 52, there areprovided-gauges 86and 81 (the casings of which are shown in Fig. 1),having dial plates88 and 89, respectively, shown in Fig. 2, upon theouter surface of the bevel top I6 of the casing ll. Thegauges 86' and 81are connected by means of small-diameter flexible tubes '90 and 9|carried inside of the flexible conduits 45*and' 46, respectively/Thesmall-diameter tubes 90 and 9| terminate in connecting elbows 92 and 93(Figs. 1, '2 and 4), which extend through the connecting thimbles 4? and48 upon the-ends of the cond uits 45 and 46, respectively, and haveattached thereto short flexible connecting'tubes 94 and 95, upon thefree ends of whichthere are secured nipples 96 and 9'! (Figs. 1 and 4),respectively. The nipples 96 and 91 are detachably connected to theouter ends of rigid'tubes 98 and 99, respectively, and are easilydisconnected when the conduits are disconnected from their correspondingtubular valve units. The rigid tubes 98 and 99 are connected to "thegauge casings 86 and 81, respectively. The gauges are of conventionalbellows type and "have air-pressure chambers into which the rigid tubes98 and 99 terminate.

In Figure 5 there is shown a means to prevent damage to the operatingparts in' theeasing when, inadvertently, an operator covers the=c0nduitopening with a hand, or otherwise, while the motor is-operating.Whilethis damage prevention-means is provided upon both conduits, asingleconduit 46 is shown. The conduit 46 terminates, as already stated,upon a thimble 54 which-carries uponit-a section of rigid tubing I60which extends outwardly beyond the end of the thimble 54. The smalldiameter tube 9| is attached to the'irmer end of the tube- 100. When theconduits are detached from the-torsoengaging shells, the projecting endof the tube lfll'lprevents any coverage of the open end of the conduitsby the operators hand, or otherwise.

A further damage prevention-means is provided upon the piston 22 andconsists of supplying, in a. groove 1 6 I, upon the periphery of thepiston 22,

a flexible gasket I62 which collapses, or bends over, as shown by brokenlines in Fig. 6, when dangerously abnormal pressure backs-up against thepiston, thereby letting the pressure escape to the opposite or back sideof the piston to establish a lessened or normal pressure within thesystem, dissipating the abnormal pressure and allowing the gasket toreturn to normal cylindercontacting and air-compressing position.

With the varying pressure of the air-flow through the large flexibleconduit, the wall of the enclosed small diameter tube is acted upon bythe alternating pressure inside of the larger conduit, and the finaleffect is for the elimination of variation of volume inside thesmalldiameter tube with the resultant increase in accuracy of measurement ofthe pressures acting upon the patient within the shell of the apparatus.

When pressure is increased inside the conduit, pressure issimultaneously increased in the tube, with negligible air-flow. Whenpressure is decreased in the conduit, pressure is simultaneouslydecreased in the tube likewise with sure-producing compressor.

Referring back'to the tubular valve units, it will be noted that eachunit includes two valve pockets, namely, GI and 62. Through the valvepocket 6| air is admitted to the flexible conduit or 46, while throughthe valve pocket 62 air is emitted from the conduit. The latter valve ispressure-closed, preferably by a flexible domed closure member that,however, is inflexible enough to prevent emission of air until thepressure of air within the conduit thereagainst is great enough to flexthe closure member. Such a member is illustrated in Figs. '7 to 12,inclusive.

The valve pockets 62 are formed with an opening I03, which connects thepocket with the tubular portion of the tubular valve unit 40 andprovidesa ledge I04 upon which is fixed, by

cementing or other siutable means, a wheelshaped disk I05 havingopenings I06 and a central hub portion I01. From the hub portion thereextends upwardly a pedestal I08, having afianged cap 109 over which isfitted a flexible closure member H0. This closure member is formed withan annular table portion III and has a central opening H2 and a coveringdome portion II3 forming a pocket II4 into which the flanged cap I09fits to hold the closure member in place. A tapered or beveled annularflange I I5 extends-downwardly from the table III and forms a closureatthe point of contact between its lower annular edge and the uppersurfac rim of the ring I05. 7

A screened air-vent H6 is formed in the top of the casing II (Fig. 2)and similar screened openings may be provided in other parts of thecasing. A pilot light II! and switch are located upon the bevel frontportion I6 of the casing II.

I claim: a 1. Respirator apparatus having a shell adapted 'to be fittedtightly to a patient's thorax, an

instrument casing having a source of positive and negative pressuredair-flows together with valve mechanism for controlling the degree ofsuch air-flows as well as a pressure-indicating gauge and a conduitassociated with the valve mechanism and the gauge for connecting theshell with said source; characterized bya connection between. theinterior of 'theshell and the gauge comprising a pressure-transmittingdevice from which such air-flows are significantly excluded so that anytendency of its interior volume to change is minimized, said devicecomprising a non-expansible tube passing through the conduit lengthwisethereof and projecting into the shell a distance greater than does theconduit.

2. Apparatus according to claim 1, with the addition that thepressure-transmitting tube has one of its ends entering the shell andone of its ends connected to the gauge while being functionally remotefrom the air-flow and the atmosphere.

3. Respirator apparatus having a shell adapted to be fitted tightly to apatient's thorax, an instrument casing having a source of positive andnegative pressured air-flows togetherfwith a pressure-indicating gaugeas well as a conduitfor connecting the shell with said source;characterized by a valve mechanism for independently controlling thedegree of each type of such air-flows comprising valves interposed inthe conduit adjacent the auge and of' which one valve is adapted forletting air into the conduit while another is adapted for emitting airfrom the conduit wherein at least one of the valves has an aperturedplate and an abut ting apertured turnable gate alinged therewith, withthe aperture in at least one of these being in the shape of anapostrophe.

4. Respirator apparatus having a shell adapted to be fitted tightly to apatients thorax, an instrument casing having a source of positive andnegative pressured air-flows including a motor-driven reciprocatingpiston in a cylinder together with a pressure-indicating gauge as wellas a conduit for connecting the shell with said source; characterized bymeans for avoiding damage to the motor drive for the piston if abnormalpressures are developed thereoncomprising a gasket between the peripheryof the piston and its cylinder that is normally inflexible enough toproduce the desired air-flows but flexible enough to bend automaticallyto permit abnormal pressures to escapepast the piston.

5. Apparatus according to claim 4, wherein the gasket is annular and isretained seated in a peripheral groove in the piston by resilience ofthe gasket material. v

. 6. Apparatus according to claim 4, wherein the conduit is-detachablefrom the instrument casing thus exposing a place where abnormal pressuremay be created by the inadvertent placing there in closin position ofthe operator's hand. I

CARL C. WILM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Date Wilm Dec. 6, 1949

